When I first started treatment, I asked my docs about wearing something to protect my teeth (metal) that would block the radiation to them. That was not possible as it would affect the beam that was directed at the tumor. I then asked about a lead apron during radiation treatments for my torso and privates. The radiation people told me that it would serve no purpose, as the doses of radiation I was getting were more than would be stopped by a little lead apron (like you wear in the dentists office), i.e. I was going to get blasted to the MAX. So I had to chuckle when I read your post. An oncologist that I spoke with today just laughed...A rubber tray blocking enough radiation to help you teeth? Not likely.